Semiconductor nanocrystals (quantum dots), specifically CdS, CdSe and CdTe, etc, have been extensively studied in the past two decades, leading to their integration in light emitting diodes (LEDs), solar cell, and bio-imaging/labeling. Although efficient deep-green, yellow, and red emissions have been realized with these nanocrystals, but quantum dots with light-green and deep-red emissions have remained elusive due to a lack of appropriate materials. Meanwhile, the intrinsic toxicity of these cadmium-containing nanocrystals is also a concern and may eventually limit many of their potential applications (specifically in human related subjects). This NIH SBIR project will develop highly bright and stable light-green and deep-red emitting quantum dots that can be used as bio-imaging agents. The proposed quantum dots contain no cadmium or other heavy metal elements, and thus would find wide applications in life and biomedical sciences. Key words: Semiconductor nanocrystals, cadmium-free quantum dots, nanocrystal production, doped nanocrystals, light-green emitting quantum dots, deep-red emitting quantum dots. PUBLIC HEALTH RELEVANCE: This SBIR project will develop highly bright and stable light-green and deep-red ZnTe based luminescent quantum dots that can be used for bioimaging application.